This application claims benefit of Japanese Patent Application No. H11-157031 filed in Japan on Jun. 3, 1999 the contents of which are incorporated by this reference.
1. Field of the Invention
This invention relates to a camera, and more particularly to a camera including at least: (i) an electronic image pickup which comprises an electronic image pickup device which includes an image pickup for performing the photoelectric conversion of an object image, (ii) a display for displaying images upon reception of image signals from the image pickup, and (iii) a flash light emitting device which emits a flash light to the object.
2. Related Art Statement
Conventionally, various proposals have been made with respect to a camera which has a following constitution. That is, the camera is comprised of an electronic image pickup device which includes image pickup means for converting an object image formed by a photographing optical system into electric signals and display means for displayig images indicative of image signals outputted from the image pickup means, and a silver salt photographing device which exposes an object image which is formed by a photographing optical system to a silver film. In such a camera, the image pickup operation of the electronic image pickup device is performed in an interlocking manner with an exposure operation applied to the silver film performed by the silver salt photographing device. Such proposals have been introduced by Japanese Laid-Open Patent Publication 114169/1989 and Japanese Laid-Open Patent Publication 108054/1998, for example.
The camera disclosed in Japanese Laid-Open Patent Publication 114169/1989 is constituted such that, simultaneous with the exposing of an object image which is formed by the same photographing optical system to a silver film, image signals indicative of the object image obtained by forming on a light reception plane of an image pickup element are outputted to a display device, and an image including the object image is displayed by the display device. With such a camera, the same image as exposed to the silver film can be confirmed by the display device even during the photographing operation.
In this know device, however, since the luminous flux of the object focused by a single photographing optical system is divided and led to the silver film and the image pickup element, the quantity of light which is to be irradiated respectively to the silver film and the image pickup element may suffer from shortage. In this case, particularly, when the object has a low luminance, a case that the quantity of light necessary for forming an image with proper exposure cannot be obtained may arise.
On the other hand, the camera disclosed in Japanese Laid-Open Patent Publication 108054/1998 is comprised of a silver salt photographing device which exposes an object image formed by the photographing optical system to the silver film and an electronic image pickup device which includes a photographing optical system separate from the photographic optical system of the silver salt photographing device, an image pickup element which converts the object image formed by this separate photographing optical system into electric signals and a display device which displays a corresponding image upon reception of image signals outputted from the image pickup element. Due to such a constitution, simultaneous with performing of the operation to expose the object image to the silver film, the image pickup operation by the image pickup means which includes the generation of image signals and the display of an image by the display device based on the image signals and the like is performed.
In such a camera, since the silver salt photographing device and the electronic image pickup device are respectively provided with separate photographing optical systems, the film and the image pickup element are irradiated with a sufficient quantity of light and hence, no shortage of the quantity of light occurs and the proper electronic image and the proper film image can be simultaneously obtained.
Further, conventionally, with respect to cameras such as silver salt photographing devices which perform photographing by using silver films and electronic image pickup devices which generate electric image signals by using the image pickup elements or the like and can display and record images based on image signals, cameras which integrally incorporate flash light emitting devices or so called strobe devices therein have been commercialized, wherein the strobe devices provide a proper luminance to main objects by irradiating auxiliary light to the object in case the luminance of the object suffers from low illumination intensity or the photographing is made under backlight and the like.
In conventional typical electronic image pickup devices and the like, it has been well known that at the time of reading out charges stored in each element on a light reception plane of an image pickup element such as a CCD at a high speed or in case the display of the image is performed by a display device such as an LCD, to be more specific, in case electricity is supplied to a backlight disposed on a back surface of the LCD so as to turn on the backlight, the quantity of electric power supplied from a power source such as a battery to respective electric members becomes large and correspondingly the consumed electric current of the device as a whole is liable to become excessively large rapidly.
Under such a condition which applies a heavy load to the power source, in case the charging operation of the flash light emitting device is further performed in parallel, the consumed electric current is further increased and hence, the power source voltage is reduced correspondingly and a case that a given amount of electric energy cannot be supplied to the image pickup device (CCD or the like) and the display device (LCD or the like) may arise.
Taking such a problem into account, a camera disclosed in Japanese Laid-Open Patent Publication 5/181183 is constituted such that, when the camera is driven under the condition that a heavy load is applied to an image pickup circuit part and a recording circuit part and the like, for example, in case the charging of the flash light emitting device such as a strobe device or the like is performed in parallel to driving of the camera, the power source voltage is constantly monitored and when the lowering of the power source voltage is detected, control to stop the charging operation under execution is performed. Then, when it is detected that the power source voltage is recovered by temporarily stopping the charging operation, control to start the charging operation again is performed. Such control is repeated until a given amount of charging is obtained.
With respect to the means disclosed in the above-mentioned Japanese Laid-Open Patent Publication 181183/1993, at the time of heavy load driving, the strobe device is controlled such that it performs the above-mentioned intermittent charging operations and hence, it takes a considerably long time for the strobe device to obtain the charging completion condition while securing a given charging amount. This implies that, compared to a normal charging operation, it takes a longer time until the condition that a next photographing operation which requires a light emitting operation of the strobe device is obtained, that is, until a given signal to allow the next photographing operation is supplied.
Accordingly, there has been a problem that at the time that a user wants to perform a photographing operation, the charging operation has not yet been completed and hence, the user loses a shutter chance since the camera is not in the condition which allows the performing of photographing.
Further, in case the photographing is performed under the condition which requires the emitting of light from the flash light emitting device, for example, under the condition that the luminance of the object is low, it is considered the flash light emitting device generates a next photographing permission signal without waiting for the completion of the charging operation of the flash light emitting device to assign priority to the shutter chance.
However, since a sufficient flash light emitting amount is not secured, images which are displayed based on image signals generated by such a photographing operation are considered to become images which suffer from the shortage of exposure.
Further, in the flash light emitting devices adopted by the conventional cameras, various electric noises are liable to be generated during performing of the charging operation. Accordingly, in case the charging operation is performed in parallel to performing of the recording operation of electric image signals and performing of the displaying operation of images based on the image signals, noises may be mixed into the recorded image signals thus giving rise to a problem that the image quality is deteriorated or the displayed images suffer from disturbance.
In Japanese Laid-Open Patent Publication 114169/1989 and Japanese Laid-Open Patent Publication 108054/1998, the above-mentioned problems are not referred to at all and there exists no description which suggests that these problems exist
The present invention has been made in view of the above-mentioned problems.
It is the first object of the present invention to provide a camera providing both silver salt photographing and electronic image pickup which is comprised of an electronic image pickup device which includes an image pickup for performing a photoelectric conversion of an object image and a display which displays an image, a silver salt photographing device for exposing an object image to a silver film, and a flash light emitting device for emitting a flash light, the improvement being characterized in that the time which is necessary from a point of time that a photographing operation was performed by using the flash light emitting device to a point of time that a condition which enables a next photographing operation becomes ready can be shortened and image signals and film images which ensure the image of a proper exposure can be always obtained.
It is the second object of the present invention to provide a camera providing both silver salt photographing and electronic image pickup which generates no trouble in the image pickup operation and the image display operation even in case the image pickup operation is performed by making use of the flash light emitting device.
To briefly explain the present invention, the first aspect of the invention is directed to a camera which includes a silver salt photographing section which is capable of exposing an object image to a silver film, an image pickup section which converts the object image into electric image signals and stores the electric signals therein in an interlocking manner with the silver salt photographic section, and a monitor which displays images based on image signals picked up by the image pickup section the improvement being characterized in that the camera further includes flash light emitting device which irradiates a flash light to an object by discharging a charge stored in a capacitor to a light emitting tube, a charging device which charges the capacitor, and control means which measures a charged voltage of the capacitor during the charging operation of the charging device and controls a display condition of the monitor in response to a result of the measurement.
Further, a second aspect of the invention is directed to a camera which includes a silver salt photographing section which exposes an object image to a silver film and an image pickup section which converts the object image into electric image signals and stores the electric signals therein, the improvement being characterized in that the camera further includes a monitor which displays images in response to the image signals picked up by the image pickup section, a flash light emitting device which irradiates a flash light to the object image by discharging the charge stored in a capacitor to a light emitting tube during the operation of the image pickup section, a charging device which charges the capacitor, and a measuring device which measures a charged voltage of the capacitor during the charging operation of the charging device and control means which permits or prohibits the display of the monitor in response to a result of the measurement.
Still further, a third aspect of the invention is directed to a camera which includes a silver salt photographing section which exposes an object image to a silver film and an image pickup section which converts the object image into electric image signals and stores the electric signals therein, the improvement being characterized in that the camera further includes a monitor which displays images in response to the image signals picked up by the image pickup section, a flash light emitting device which irradiates a flash light to an object by discharging a charge stored in a capacitor to a light emitting tube during the operation of the image pickup section, a charging devices which charges the capacitor, and control means which prohibits at least the operation of the image pickup section and the operation of the monitor until the charged current of the charging means becomes equal to or less than a given value.
A fourth aspect of the invention is directed to a camera which exposes an object image to a silver film and is comprised of an image pickup circuit which includes an image pickup element which picks up an object image, a drive circuit which drives the image pickup element, a signal processing circuit for processing image signals picked up by the image pickup element, a display circuit which performs processing for displaying images based on image signals processed by the image pickup circuit, a strobe circuit which includes a flash light emitting tube, a capacitor for strobe, a charging circuit which makes the capacitor store the charge therein, a measuring circuit which measures the charged voltage of the capacitor and a light emitting circuit for performing processing for discharging charges stored in the capacitor in the flash light emitting tube, and a control circuit which supplies control signals to respective circuits, wherein the control circuit performs control such that, after operating the charging circuit, the control circuit prohibits processing for display performed by the display circuit until the measuring circuit detects that the charged voltage of the capacitor reaches a given value.
These and other objects and advantages of the present invention will become further apparent from the following detailed explanation.
The present invention provides a camera providing both silver salt photographing and electronic image pickup which is comprised of an electronic image pickup device which includes image pickup means for performing a photoelectric conversion of an object image and a display which displays images, a silver salt photographing device for exposing an object image to a silver film, and a flash light emitting device for emitting a flash light, and is capable of immediately performing a next photographing operation after performing the photographing operation by using the flash light emitting device and is always capable of obtaining image signals which ensure images of a proper exposure.
Further, the present invention provides a camera providing both silver salt photographing and electronic image pickup which generates no trouble in the image pickup operation and the image display operation even in case the image pickup operation is performed by making use of the flash light emitting device.